The invention relates to portable objects equipped with an electronic circuit adapted to form a binary coded identification signal--circuit called "badge" below--, the coded signal being identifiable by an interrogator-reader situated at a short distance from the object, without direct contact with it.
It relates more particularly, among these objects, to those whose badges are "passive", that is to say do not carry any source of electrical energy, the supply of each badge being ensured by an inductive coupling of a component of this badge with an external component in which an electrical voltage is generated at high frequency F.
It is also directed at devices enabling the "reprogramming" of the badges concerned, that is to say the changing of the codes which are recorded in these badges and which serve for forming the coded identification signals.
It is to be noted that, each badge identification being effected at a distance, without metallic contact, it is possible to place this badge inside an electrically insulating envelope which is completely closed and sealed, which is advantageous for the protection and hence the longevity of the badge.
The existence of this envelope excludes the use of metal contacts for reprogramming codes and it is hence necessary to effect the transmission of the different orders ensuring this reprogramming by means of electromagnetic couplings, particularly inductive, passing through said envelope.
Now, in the embodiments proposed hitherto, such reprogramming of the badges was effected:
either through metal contacts,
or through coupling at a distance, particularly inductive coupling, but then only in the case where the badge to be reprogrammed was "autonomous", that is to say possessed itself a source of electric power.
The current consumption required for the writing, the reading and the rewriting of the memories in which the identification codes of the badges were recorded required in fact recourse to several continuous voltages of different amplitudes, of which amplitudes the largest was relatively high.